23: Design Output Incorrect
Definition/Typical Issues
Were there problems with management practices to track design requirements and relate them to the design outputs? Did the specifications fail to include all of the requirements? Were some criteria left out of the design output?
Were the drawings and other specifications incorrect? Should prototype tests have been conducted but were not? Were compatibility studies and tests performed?
Note 1: If the design output was incorrect because the design input was incorrect, that should be coded under the Design Input Issue (#19) node.
Examples
Example 1
- During the initial design review, the company requested that an additional flow indication be added in the cooling water line. The requirement was added to the design requirements document. However, this requirement was never transmitted to the design staff. As a result, the item was not addressed in the design drawings for the system. The system subsequently failed in service.
Example 2
- The design specification for a fired heater (i.e., a heater that uses a flammable gas as the heat source) did not address all of the applicable design standards noted in the design specification. This resulted in a near miss in that the situation was detected just before the heater failed.
Example 3
- A display did not show the appropriate range of flow during an emergency. The display did not account for emergency and unusual operation conditions because the design requirement was never addressed. As a result, the operator failed to respond to the emergency properly.
Example 4
- The design documentation for a new flare tower showed an incorrect line tie-in for a modification. As a result, excessive corrosion of the tower occurred.
Typical Recommendations
- Develop an independent review process to be used during the design process to help ensure that all of the design inputs are addressed in the final output.
- Develop a tracking system to help ensure that all design inputs are addressed in the design output.
- Develop a tracking system for specification changes and design changes to help ensure that the final design includes all changes.
- Develop an independent review process to help ensure that appropriate standards are used in the design.
- Develop an independent review process during design to help ensure that calculations and analyses are correct and complete.
Cross-References
| Version 10 Element(s) | |
|---|---|
| Node ID | Node Name |
| 17 | Design Output LTA |
| Maritime Element(s) | |
|---|---|
| Node ID | Node Name |
| 28 | Design Output Incorrect |
| 30 | Design Input Not Addressed in Design Output |